Boot your Mac into FireWire Target Disk Mode (with the T key held down at startup)

Then go to someone elses Mac and connect the two with a standard FireWire cable. Boot their Mac with the Panther CD (in their computer) and install it onto your iBook's hard drive (your iBook's hard drive will appear as a Firewire device)

Alternatively borrow a FireWire Optical Drive and boot off that.

On a seperate point I would recommend a clean install rather than an upgrade - much less potential issues.

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